Research On Electronic Current Transformer

With the increase of the power transmission capacity and grid voltages, the traditional electromagnetic current transducer has shown its weakness. Electronic Current Transformers show their opposite advantages: no danger of explosion; no magnetic saturation; no danger of high voltage via optical path output in case of open circuit; not sensitive to electromagnetic interference; direct output of digital signals. So it is the trend of ECT to replace electromagnetic current transducer. ECTs have win great attention from researchers and professionals all over the world.Under such circumstances, in this paper, the basic principle of ECTs and the design theory is introduced. The performances of linear sensing element, filter, integrator are theoretically analyzed; the digital signal processing schemes on temperature compensation and non-linear compensation of ECTs output characteristics are discussed; an method used for field adjustment to ECTs is proposed to carry out adjustment of ECT in the grid field. An ECT prototype is developed based on the schemes reported in this paper. The test report given by the National Current Transducer Examination Center (NCTEC) shows that the prototype ECT can fulfill all the requirements of IEC's and National standards. The result proved that the digital process schemes and the field adjustment scheme reported in this dissertation and used in the prototype are reasonable and feasible.